1.3 Bonding Flashcards
Metalic bond
Attraction between positive metal ions and delocalised electrons
Ionic bond
Electrostatic attraction between oppositely charged ions
Which elements do not form ions?
Boron
Carbon (usually)
Silicon (usually)
What ions does tin form?
Sn⁴⁺ (most stable) and Sn²⁺
What ions does lead form?
Mostly Pb²⁺ but some Pb⁴⁺
Covalent bond
A shared pair of electrons
What is a lone pair?
A pair of electrons which are not bonded
What are non-octet molecules?
Molecules where the central atom does not have a noble gas electron arrangement
Coordinate bond
A covalent bond in which both electrons of the shared pair come from the same atom
How does a lone pair effect the bond angle?
Reduces angle by 2.5 degrees
Electronegativity
The power of an atom to attract the pair of electrons in a covalent bond
Most electronegative atom
Fluorine
Why does electronegativity increase across a period?
The number of protons (nuclear charge) increases
Why does electronegativity decrease down a group?
Atomic radius increases as the number of shells increases
Why don’t the noble gasses have electronegativity values?
They do not usually form covalent bonds
Three types of intermolecular force
- van der Waals’s forces
- Permanent dipole-dipole forces
- Hydrogen bonds
Electron deficient
Where the central atom of a non-octet molecule has fewer electrons than the noble gas configuration
Expanded octet
Where the central atom of a non-octet molecule has more electrons than the noble gas configuration
Shape:
2 bond pairs
0 lone pairs
Linear
(180°)
Shape and angle:
3 bond pairs
0 lone pairs
Trigonal planar
(120°)
Shape and angle:
4 bond pairs
0 lone pairs
Tetrahedral
(109.5°)
Shape and angle:
5 bond pairs
0 lone pairs
Trigonal bipyramidal
(90° and 120°)
Shape and angle:
6 bond pairs
0 lone pairs
Octohedral
(90°)
Shape and angle:
2 bond pairs
1 lone pairs
V-shaped
(117.5°)
